}
			coverage[a] = true
		}
	}
	if len(coverage) != 9 { // TODO: can we cover all outputs?
		t.Errorf("coverage too small, got %d want 9", len(coverage))
	}
}

func TestSubFlagsNative(t *testing.T) {
	var numbers = []int64{
		1, 0, -1,
		2, -2,
		1<<63 - 1, -1 << 63,
	}
	coverage := map[flagConstant]bool{}
	for _, x := range numbers {
		for _, y := range numbers {